IHMS said that as of midnight on March 31, it had been forced to temporarily stop operations to resolve an ongoing medical licensing issue.

It said the PNG Medical Board asserted that the IHMS clinic was not licenced, but the company claimed it had submitted all the necessary documentaiton.

In a statement, IHMS said it would not continue to provide services under such conditions, but that it hoped to resume services "in the very near future."

"Despite extensive representations by IHMS and the Australian Government, the PNG Medical Board has to date only renewed the Authorities to Practice for 27 percent of staff, meaning that the majority are unregistered to practice in PNG."

IHMS said a number of contingencies had been put in place to ensure emergency response capability.

The company's time on Manus Island has been plagued by controversy.

In March, an independent review committee sanctioned by the PNG government found the IHMS parent, International SOS, had not been licensed under the Medical Registration Act to operate its Manus Island facility.

The government said the committee had also found ISOS had broken other laws regarding labour, tax evasion and immigration.

In response, IHMS said it was licensed to dispense services on Manus, where it employs 130 staff under contract with the Australian Immigration Department.

It said it had "received conflicting advice from the PNG Government regarding who should hold the license."

"Overlaying the licensing issue, as a result of competing commercial interests within the healthcare sector in PNG, IHMS has been the target of multiple unfounded accusations including that IHMS has not complied with PNG labour, immigration and taxation laws. IHMS provided the PNG Government all the information required to refute these allegations. "

In March 2015, an investigation by the Guardian revealed IHMS had failed to meet medical targets and deliberately included incorrect data in reports to the department.

Reviews commissioned by the department found it had failed to appropriately oversee IHMS operations.

In 2016, a Queensland coroner's inquest into the death of detainee Hamid Kehazaei heard that the IHMS and the department blamed each other for Mr Kehazaei's delayed and deficient treatment.

The 24-year-old refugee from Iran died in 2014 after complications that arose from a treatable leg infection.

Hamid Khazaei Photo: supplied

In audio recorded on Friday by the Kurdish journalist and Manus Island detainee, Behrouz Boochani, an Australian Border Force spokesperson told the centre's roughly 900 inmates that in the absence of IHMS, Paradise Private Hospital in Port Moresby would prioritise all essential health services.

Mr Boochani said detainees had lost confidence in IHMS after refugees died under its watch.

He said the company should be held accountable for facilitating Australia's offshore detention of refugees and for not providing adequate services.

"Hundreds of refugees are seriously sick and need medical treatment. We have a logical fear of our medical needs being neglected again. "